This invention relates to radar detection in general and more particularly to detection of moving targets interrogated by emission of radiant energy reflected from such targets as echo pulses to be picked up by an optical receiver producing Doppler signals that are processed and readout to provide target motion data. Such a radar system is covered in our prior related U.S. application Ser. No. 07/687,602, now U.S. Pat. No. 5,095,312 filed Apr. 12, 1991, (now U.S. Pat. No. 5,095,312) the disclosure of which is incorporated herein by reference.
Doppler radar systems of the foregoing type are also disclosed for example in U.S. Pat. Nos. 2,821,702, 2,885,668 and 4,131,889 to Russell, Eaton and Gray, respectively. According to the foregoing patents separate pulse transmitting and echo pulse receiving antennas are featured. Signal processing according to the Gray patent includes internal generation of a reference signal utilized through a mixer to correlate impulse transmitter operation with reception of target reflected radiation. According to the Russell patent, operation of the impulse transmitter is controlled through a transmit/receiver switch.
Conventional Doppler radar systems as well as those disclosed in the foregoing referred to patents suffered from various motion readout problems because of signal clutter and an inability to isolate the radiant energy reflections from the moving targets being monitored to provide accurate readout information thereon. It is therefore an important object of the present invention to overcome the foregoing deficiencies of prior art Doppler radar systems.